Clinical Hemorheology and Microcirculation - Volume 47, issue 2

Authors: Blankfield, Robert P.

Article Type: Research Article

Abstract: Fluid retention increases intravascular volume and pressure. The calculations in this paper demonstrate that fluid retention increases the likelihood that blood will flow in a turbulent manner, in part due to an increase in stroke volume, regardless of whether or not blood pressure is increased. Increased turbulence will promote endothelial dysfunction, thereby contributing to the development of atherosclerotic cardiovascular disease. Accordingly, fluid retention is predictably detrimental to the cardiovascular system. The reason that some medications, such as cyclo-oxygenase-2 inhibitors, nonselective nonsteroidal anti-inflammatory drugs, estrogens, progestins, and rosiglitazone, are associated with an increased risk of myocardial infarcts and strokes may be …that they cause fluid retention. Increased stroke volume and/or edema formation may indicate that a medication increases the risk of adverse cardiovascular events. For drugs that increase the risk of adverse cardiovascular events, it may be possible to reduce or neutralize the increased risk by simultaneously administering a diuretic. Show more

Keywords: Fluid retention, stroke volume, velocity of blood flow, turbulence, atherosclerosis

DOI: 10.3233/CH-2010-1369

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 79-86, 2011

Authors: Al-Tahami, Belqes Abdullah | Bee, Yvonne-Tee Get | Ismail, Abdul Aziz Al-Safi | Rasool, Aida Hanum Ghulam

Article Type: Research Article

Abstract: Introduction: This study aims to assess microvascular endothelial function in obese compared to age matched lean controls. Serum lipid profile, fasting glucose, high sensitivity C-reactive protein (hs-CRP) and adiponectin levels were also determined. Methods: This cross-sectional study involved 36 healthy lean and 36 obese subjects. Microvascular endothelial function was assessed using Laser Doppler fluximetry and iontophoresis with acetylcholine and sodium nitroprusside. Results: Mean age of subjects was 26.54 ± 0.60 years. Obese subjects had higher systolic (118.8 ± 1.5 vs 105.7 ± 2.0mmHg, p < 0.001) and diastolic blood pressure (71.61 ± 1.35 vs 64.53 ± 1.40mmHg, p = 0.001), …higher triglyceride (1.35 ± 0.13 vs 0.79 ± 0.05 mmol/l, p < 0.001), lower high density lipoprotein cholesterol (HDL-C) (1.43 ± 0.04 vs 1.62 ± 0.05 mmol/l, p = 0.003), higher hs-CRP (11.58 ± 1.88 vs 1.88 ± 0.35 mg/l, p < 0.001), and lower adiponectin levels (8.80 ± 0.43 vs 25.93 ± 0.40 μg/ml, p < 0.001) compared to lean subjects. Endothelial dependent vasodilatation was lower in obese compared to lean subjects (40.53 ± 6.59 vs 71.03 ± 7.13 AU, p = 0.001). Conclusion: Microvascular endothelial function is reduced in obese compared to age matched controls. This is associated with higher BP, triglyceride and lower HDL-C and adiponectin levels in obese group. Show more

Keywords: Obesity, microvascular endothelial function, metabolic markers, adiponectin

DOI: 10.3233/CH-2010-1370

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 87-97, 2011

Authors: Häfner, Hans-Martin | Bräuer, Kurt | Kneilling, Manfred | Moehrle, Matthias | Breuninger, Helmut

Article Type: Research Article

Abstract: Primary closure in dermatologic surgery is state of the art in small lesions at the head, but also in larger lesions at the trunk or the extremities. Microcirculatory effects on the skin blood flow near to the wound edges affected by primary closure. Forty three patients were investigated. Before and after surgery, skin blood flow was measured using Laser Doppler Fluxmetry (LDF). During primary closure, tension in the suture was measured and the tension on the wound edges was calculated. Times series were analyzed using continuous wavelet analyses, before, after 2 h and 24 h after surgery. After three months, …the cosmetic results were requested. Median horizontal diameter was 22 mm (quartiles 20/48 mm), median vertical diameter was 44 mm (quartiles 26/60 mm). Mean string force was 12.0 SD 10.2 N. During the whole course of investigation, we found no change of microcirculatory parameters such as mean LDF or any scaling level following wavelet analysis caused by primary closure. Average of the cosmetic result was 1.8. It is a relative small number of patients and the defects are located in different areas. Skin blood flow and the microcirculatory pattern is not affected in the area by the tension on wound edges and provides therefore a fast healing process without any vegetatively induced complications even if the string force is high. In dermatosurgery, wounds can be closed directly without changing the microcirculatory pattern in the direct area of the wound margins. Show more

Keywords: Primary closure, dermatosurgery, microcirculation, cosmetic result, wavelet analysis, laser doppler flux

DOI: 10.3233/CH-2010-1371

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 99-109, 2011

Authors: Simmonds, Michael J. | Baskurt, Oguz K. | Meiselman, Herbert J. | Marshall-Gradisnik, Sonya M.

Article Type: Research Article

Abstract: There is accumulating evidence that exercise may improve disturbed haemorheological parameters that are typically observed in various chronic diseases, thus there is a growing interest in exploring the influence of various exercise models for the improvement of haemorheology. Blood sampling using venipuncture, however, can be limiting during exercise and/or in field settings. The purpose of the present study was to investigate whether venous and capillary blood samples yield comparable red blood cell (RBC) deformability and aggregation indices. Twelve healthy volunteers (6 males and 6 females; age 30 ± 9 yrs; body mass index 24.9 ± 2.8 kgm−2 ) provided blood …samples that were collected simultaneously from: i) a prominent forearm vein by venipuncture; ii) the earlobe using a lancet; iii) the middle finger using a lancet. Haematocrit, RBC deformability (Rheoscan-D, Sewon Meditech Inc., Korea) and RBC aggregation (Myrenne GmbH, Roetgen, Germany) were measured for each sample. Haematocrit and RBC deformability were not different between the three sampling sites, and the group averages of RBC aggregation parameters were not different between the three sampling methods. The time course of RBC aggregation was slower when using blood sampled from the earlobe, and there was stronger agreement between RBC aggregation parameters measured using venous and capillary finger samples compared with venous and earlobe. It is suggested that capillary blood sampling from the finger may provide a reliable alternative to venous blood sampling in clinical and field settings. Show more

Keywords: Aggregation, agreement, deformability, earlobe, erythrocyte, finger, red blood cell

DOI: 10.3233/CH-2010-1372

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 111-119, 2011

Authors: Ramos, S.B. | Brun, J.F. | Gray, B. | Rogerson, S. | Weatherby, R.P. | Tajouri, L. | Marshall-Gradisnik, S.M.

Article Type: Research Article

Abstract: Introduction: It has been shown that growth hormone (GH) exerts regulatory effects on hemorheology and other metabolic functions. GH stimulates the production of insulin-like growth factor I (IGF-I) and GH–IGF-I system has profound effects on body fluid status. There are speculations that GH has become widely used as a performance enhancing drug among athletes of various sports. The present study evaluated the possible hemorheological effects of short term administration of human recombinant growth hormone (rhGH) in healthy young males. Methodology: Thirty young healthy males (27 ± 9) participated in a 29 days study where it was administered either 0.9% sodium …chloride or 1 mg of human rhGH from day 1 to day 7. The participants were randomly assigned into either placebo (C) n = 15 or rhGH 1 mg/day (rhGH) group n = 15. This study evaluated plasma fibrinogen levels, red blood cell (RBC) aggregation, deformability and serum IGF-I levels between and within the groups along 29 days. Results: There was a significant increase in erythrocytes aggregation index post injection (day 8), in accordance to an increase in serum IGF-I. Show more

Keywords: rhGH, aggregation, deformability, fibrinogen, IGF-I

DOI: 10.3233/CH-2010-1373

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 121-129, 2011

Authors: To, Wilson J. | Telander, David G. | Lloyd, Maureen E. | Chen, Peter C.Y. | Cheung, Anthony T.W.

Article Type: Research Article

Abstract: We hypothesized that T2DM vasculopathy can be revealed and quantified in the bulbar conjunctiva prior to its pathologic presentation in the retina. Using computer-assisted intravital microscopy (CAIM), an objective, non-invasive approach can provide a viable complement to retinal fundus photography to possibly screen patients for early signs of real-time, in vivo T2DM vasculopathy. Fundus photography was utilized to determine the retinopathy level (RL) in T2DM patients with non-proliferative diabetic retinopathy (NPDR) and control subjects. CAIM was used to quantify microangiopathy in the bulbar conjunctiva in the same patients, and reported on a severity index (SI). The average RL for the …T2DM patients in this study is 19.68 ± 9.91, which differs from control subjects (RL = 10 ± 0.0; p < 0.05). A significant difference in vasculopathy was observed in the conjunctival microcirculation in the same patients (SI = 5.81 ± 1.30) when compared with control subjects (SI = 1.33 ± 1.58; p < 0.05). The results provide evidence that significant vasculopathy had developed in the microcirculation in the bulbar conjunctiva, though diabetic retinopathy had not developed significantly in the same patients – indicative of the presence of a time window for early intervention of T2DM before non-proliferative retinopathy develops, and the real-time availability of the conjunctival microvasculature as an in vivo platform to monitor disease progression. Show more

DOI: 10.3233/CH-2010-1374

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 131-141, 2011

Authors: Kenyeres, P. | Rabai, M. | Toth, A. | Kesmarky, G. | Marton, Zs. | Alexy, T. | Toth, K.

Article Type: Research Article

Abstract: Ektacytometry quantifies erythrocyte deformability by measuring the elongation of suspended red blood cells subjected to a range of shear stresses. Raw shear stress-elongation index plots are difficult to interpret and thus data reduction methods characterizing the relationship using few parameters without loss of information and good reproducibility are essential, especially for the clinician. Two such curve fitting formulas, used widely in the literature for this purpose, are reviewed herein. The Lineweaver-Burke method overestimates maximal deformability if shear stresses below 1 Pa are applied. A modified version of the formula estimates maximal deformation more accurately but gives little weight to data …at low shear stresses. Neither method is accurate if negative elongation indices are present (artifact phenomenon when measurement is performed from high to low shear stresses). The Streekstra-Bronkhorst method provides efficient data reduction though the theoretical background of the formula is incorrect. The parameters have expressive meaning; however, both maximal and minimal deformations are slightly underestimated. Moreover, parameters are biased according to the range of measured shear stresses. Show more

DOI: 10.3233/CH-2010-1375

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 143-150, 2011

Authors: Varlet-Marie, Emmanuelle | Brun, Jean-Frédéric

Article Type: Research Article

Abstract: Bioelectrical impedancemetry (BIA) has been used to evaluate hemorheological parameters in vitro, and whole body impedance measurements are also correlated to some hemorheologic factors, due to their close relationship with determinants of electric properties of blood. In previous studies, we have determined a set of predictive equations for hematocrit, whole blood viscosity and plasma viscosity in both sedentary and trained individuals. Recent developments of the interpretation of BIA analysis based on Hanai's mixture conductivity theory allows a more interpretative analysis of the relationships between these electric measurements and body composition. Impedance can be analyzed in terms of resistance and resistivity …of the whole body and even more, assuming some simplifications, resistance R and resistivity ρ of total body water (TBW), extracellular water (ECW) and intracellular water (ICW). In this study we thus investigated relationships between blood rheology and these calculations of R and ρ in a sample of 83 subjects (age: 9–64 yr; BMI: 17–44 kg/m2 ). BIA was performed with a multifrequency bioelectrical impedancemeter using low intensity at the following frequencies: 1, 5, 10, 50 and 100 kHz. Viscometric measurements were done with a falling ball viscometer. Hematocrit was measured with microcentrifuge. We found a new prediction of Quemada's viscometric index of RBC rigidity “k” which was positively correlated to the resistance of ECW (Re ) and even more if it was related to this volume: k = 0.005809 Re /ECW + 1.1784 (r = 0.487; Bland-Altman mean difference: 0.0124; range: −0.00481 to 0.00296). A new finding was that red blood cells (RBC) aggregability, that in the previous studies was not related to whole body impedance, despite its in vitro measurability with such measurements, was correlated to extracellular resistance and resistivity. The Myrenne index “M” was negatively correlated to the resistivity of the extracellular fluid ρe and is predicted by: M = −27.4755 ρe + 1121.57029 (r = 0.463; Bland-Altman mean difference: 0.00194; range: −0.842 to 0.842). Furthermore, the SEFAM index “S10 ” is correlated to the ρe and is predicted by S10 = −59.38579 (ρe −40) + 63.083 (r = 0.761; Bland-Altman mean difference: 0.000722; range: −1.77 to 1.77). Therefore, a more in-depth analysis of electric properties of the body provides a closer approach of RBC rheology, although, of course, most remains to be understood in this intriguing domain. Show more

Keywords: Impedance, resistance, resistivity, body fluids, hematocrit, blood viscosity, plasma viscosity, hemorheology, erythrocyte aggregation

DOI: 10.3233/CH-2010-1378

Citation: Clinical Hemorheology and Microcirculation, vol. 47, no. 2, pp. 151-161, 2011